Inventories (Schedule of Inventories) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Inventory, Net [Abstract]
Separative work units inventory	$ 3.2	$ 21.9
Uranium inventory	187.5	284.5
Inventories	190.7	306.4
Separative work units owed to customers and suppliers	0.3	0.0
Uranium owed to customers and suppliers	0.5	84.3
Inventories owed to customers and suppliers	0.8	84.3
Separative work units net of liability	2.9	21.9
Uranium inventory net of liability	187.0	200.2
Inventories, net	$ 189.9	$ 222.1